<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style>
.box{width:300px; height:150px; border:10px solid red; margin:100px;}
.small{width:100px;height:100px; background-color:#030; margin-left:-50px; position:relative;}
</style>
</head>

<body>
<div class="box">
	<div class="small"></div>
</div>
</body>
</html>
